Kentucky lawmakers heard testimony Thursday over a proposal to ban machine gun conversion devices (MCDs), also referred to as “Glock switches” or “auto sears,” that convert semi-automatic weapons into fully automatic ones.
These small devices, less than the size of a quarter, are attached to the back of a pistol. They can be made of metal or plastic– with many being made by 3D printers– and are already illegal under federal law. The possession of one constitutes a Class C federal felony.
Republican Rep. Jason Nemes of Jefferson County said he plans to introduce a bill outlawing MCDs at the state level in the 2026 legislative session. Twenty-six other states have already adopted similar bans.
“It mirrors federal law, which already says that these devices are unlawful, and it makes it unlawful in Kentucky as well,” Nemes said. “Why is that important? Because right now [local law enforcement are] not allowed to enforce federal law, obviously, with the state. So we need a state law.”
Currently, state and local law enforcement in Kentucky must rely on federal agents to charge and prosecute individuals in possession of MCDs.
Paul Humphrey, the head of the Louisville Metro Police Department, told lawmakers that many of these cases are not picked up by the Bureau of Alcohol, Tobacco, Firearms and Explosions (ATF) due to high caseloads and limited resources.
“This type of legislation gives us [the] primary ability as an officer to encounter people like this and be able to take serious enforcement action, because we understand the impact of the violent crimes that are going on on our streets and our neighborhoods, and this is exacerbated greatly by this problem,” Humphrey said.
Alabama Democratic state Rep. Phillip Ensler told members of the Kentucky Interim Joint Judiciary Committee that an MCD ban in his state came in response to high-profile shootings where such devices were used.
“On a more personal level, and certainly in my district, I know how traumatized, how hurt families were, loved ones, young people were from losing people that they knew in these really horrible mass shootings. So there was increasingly an understanding that there was a need for a state level ban,” Ensler said.
Ensler said Alabama has already seen positive effects from the ban, which was passed earlier this year. .
“Hundreds of these devices have been taken off the streets. Of course, we can’t count every time a life has been saved or a crime has been prevented, but just knowing that hundreds of these have been confiscated on the state level and local level really makes a tremendous difference,” he said.
Some officials, like Republican Rep. Savannah Maddox of Dry Ridge, voiced opposition to the proposed Kentucky ban. She had concerns over additional gun restrictions from the state.
“It is creating a new regulation, more gun control on our Second Amendment rights if we were to pass this into Kentucky’s law, regardless of what is transpiring at the federal level,” Maddox said. “I view this as new and additional gun control, and I have some issues with it. I’m opposed to it.”
Nemes argued that the bill would not impose any new restrictions since the devices are already banned federally.
“It does not make anything unlawful that is currently lawful. I cannot possess an auto sear today. It violates federal law and that does not change. It will violate state law as well [under the proposal], but it’s already unlawful. It does not take away anybody’s right that they currently have,” Nemes said.
GLOCK, Inc. voiced support of Nemes’s proposal in a letter addressed to Republican Rep. Daniel Elliott, who co-chairs the judiciary committee. The corporation denounced the illegal modification of its firearms and emphasized that “Glock switches” are not endorsed by nor affiliated with GLOCK.
